The TCM can either
receive data from the Engine Control Module or ABS control module, or it
can send data to the ECM and ABSCM by using CAN communication. The CAN
communicaton is one of the vehicle communications method, which is now
widely used to transfer the vehicle data.
When the TCM cannot read
the data from the ECU through the CAN-BUS line, the TCM sets this
code.
CAN-BUS circuit
malfunctioning or ECU can be a posssible cause of this DTC.
Item
|
Detecting
Condition
|
Possible cause
|
DTC Strategy
|
| •
|
Check the
communication | |
| •
|
Short or Open in CAN communication
circuit. |
|
Enable Conditions
|
| •
|
10.2V <Battery voltage
<15.5V |
|
Threshold Value
|
| •
|
TCU cannot receive
EMS1 | |
Diagnostic Time
|
| •
|
more than 2 times × more than 0.25
sec | |
Fail Safe
|
| •
|
Self learning control is
inhibited. |
| •
|
Adaptive control is
inhibited |
| •
|
Engine torque =
maximum |
| •
|
Gear position = 3rd
gear |
| •
|
Wheel speed = Output
speed |
| •
|
Engine coolant temp. =
80°C | |
| 1. |
Connect scantool to data link
connector(DLC). |
| 3. |
Monitor the "CAN COMMUNICATION SERVICE DATA
(ENGINE RPM, VEHICLE SPEED SENSOR, THROTTLE P. SENSOR)" parameters
on the scan tool.
|
| 4. |
Does "CAN BUS LINE DATA" follow the reference
data?
|
|
▶ Fault is
intermittent caused by poor contact in the sensor's and/or
TCM(PCM)'s connector or was repaired and TCM(PCM) memory was
not cleared. Thoroughly check connectors for looseness, poor
connection, bending, corrosion, contamination, deterioration
or damage. Repair or replace as necessary and go to
"Verification of Vehicle Repair" procedure.
|
|
|
▶ Go to
"Terminal and connector inspection"
procedure.
|
|
| Terminal And Connector
Inspection |
| 1. |
Many malfunctions in the electrical system are
caused by poor harness and terminal condition. Faults can also be
caused by interference from other electrical systems, and mechanical
or chemical damage. |
| 2. |
Thoroughly check connectors for looseness,
poor connection, bending, corrosion, contamination, deterioration,
or damage. |
| 3. |
Has a problem been found?
|
|
▶ Repair as
necessary and go to "Verification of vehicle Repair"
procedure.
|
|
|
▶ Go to
"Signal circuit inspection"
procedure.
|
|
| Signal Circuit
Inspection |
| 1. |
Ignition "OFF" & Engine
"OFF". |
| 2. |
Disconnect the "ECU"
connector. |
| 3. |
Measure Resistance between "CAN HIGH" terminal
and "CAN LOW" terminal.
Specification
: Approx. 120±10Ω
| |
| 4. |
Is measured resistance within
specifications?
|
|
▶
Substitute with a known-good PCM/TCM and check for proper
operation. If the problem is corrected, replace PCM/TCM as
necessary and then go to "Verification of Vehicle Repair"
procedure.
|
|
|
▶ Check
connectors for looseness, poor connection, bending, corrosion,
contamination, deterioration or damage of ECM.and then Repair
or replace Resistance for CAN communication as necessary and
go to "Verification of Vehicle Repair"
procedure.
|
|
NOTE)
When replacing the TCU,
must perform the N position learning and the Initial learning. (refer to
Troubleshooting's 'How to perform N position learning' and 'How to perform
initial learning')
| Verification of Vehicle
Repair |
After a repair, it is
essential to verify that the fault has been corrected.
| 1. |
Connect scan tool and select "Diagnostic
Trouble Codes(DTCs)" mode |
| 2. |
Using a scantool, Clear
DTC. |
| 3. |
Operate the vehicle within DTC Enable
conditions in General information. |
| 4. |
Are you DTCs present?
|
|
▶ Go to the
applicable troubleshooting procedure.
|
|
|
▶ System
performing to specification at this
time.
|
|
